121665901 has 16 divisors (see below), whose sum is σ = 143152128. Its totient is φ = 101232000.

The previous prime is 121665893. The next prime is 121665941. The reversal of 121665901 is 109566121.

It is a cyclic number.

It is not a de Polignac number, because 121665901 - 2³ = 121665893 is a prime.

It is a super-2 number, since 2×121665901² = 29605182932283602, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121665941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63051 + ... + 64951.

It is an arithmetic number, because the mean of its divisors is an integer number (8947008).

Almost surely, 2^121665901 is an apocalyptic number.

It is an amenable number.

121665901 is a deficient number, since it is larger than the sum of its proper divisors (21486227).

121665901 is a wasteful number, since it uses less digits than its factorization.

121665901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2172.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 121665901 is about 11030.2266975797. The cubic root of 121665901 is about 495.5144140401.

The spelling of 121665901 in words is "one hundred twenty-one million, six hundred sixty-five thousand, nine hundred one".